Yokogawa Single Channel Oxygen Analyzer System ZR22/ZR402 - Manual (Page 168)

IM 11M12A01-03E 10-20
10.5.3 Calibration Gas Flow
<Preparation before calibration>
(1) To operate the standard gas unit, place it on a nearly horizontal surface in order to
allow the flow check to indicate the precise flow rate. In addition, a power supply for
driving the span gas (air) supply pump is required near the unit (the length of the
power cord attached to the unit is 2 m). Select a suitable location for the unit near
the installation site of the converter.
(2) Connect the tube connector port of the standard gas unit to the calibration gas inlet
of the detector, using a polyethylene resin tube with an outside diameter of 6 mm. Be
careful to prevent gas leakage.
(3) Fully open the needle valve mounted on the calibration gas inlet of the detector.
(4) Enter the oxygen concentration of the sealed gas (noted from the cylinder) into the
converter. Also check that the oxygen concentration of the span gas is correctly set
(21 vol% O
2 for clean air). When using the ZO21S Standard Gas Unit (for use of the
atmospheric air as a span gas), use a hand-held oxygen analyzer to measure the
actual oxygen concentration, and then enter it.
<Flow of span gas (air)>
The standard gas unit is used only when manual calibration is employed. Therefore, the
timing for flowing span gas (air) is included in the manual calibration flowchart de-
scribed in Section 10.5.2. For operation of the converter, see Section 7.12, earlier in this
manual.
(1) When the message “Did you open span valve Y?” is displayed on the converter
display during calibration, plug the power cord into the power supply socket to start
the pump of the standard gas unit.
Enter
Open span gas valve.
Set flow span gas to
600ml/min.
Valve opened
᭜ Cancel calibration
Manual calibration
F10.15E.EPS
Figure 10.15 Manual Calibration Display
(2) Next, adjust the flow rate to 600
±
60 ml/min using the span gas valve “AIR” (the
flow check ball stops floating on the green line when the valve is slowly opened). To
rotate the valve shaft, loosen the lock nut and turn it using a flat-blade screwdriver.
Turning the valve shaft counterclockwise increases the flow rate.
(3) After adjusting the flow rate, tighten the valve lock nut.
(4) Select Valve opened (to start calibration) from the Manual calibration display shown
in Figure 10.15. Check the Trend graph display to see that the measured value is
stabilized. Then press the [Enter] key. The Manual calibration display shown in
Figure 10.16 appears. Disconnect the power cord to stop the pump.